package audio

import (
	"fmt"
	"sync/atomic"
	"time"

	"github.com/jetkvm/kvm/internal/logging"
	"github.com/rs/zerolog"
)

// AudioInputIPCManager manages microphone input using IPC when enabled
type AudioInputIPCManager struct {
	metrics AudioInputMetrics

	supervisor *AudioInputSupervisor
	logger     zerolog.Logger
	running    int32

	// Connection monitoring and recovery
	monitoringEnabled   bool
	lastConnectionCheck time.Time
	connectionFailures  int32
	recoveryInProgress  int32
}

// NewAudioInputIPCManager creates a new IPC-based audio input manager
func NewAudioInputIPCManager() *AudioInputIPCManager {
	return &AudioInputIPCManager{
		supervisor: NewAudioInputSupervisor(),
		logger:     logging.GetDefaultLogger().With().Str("component", AudioInputIPCComponent).Logger(),
	}
}

// Start starts the IPC-based audio input system
func (aim *AudioInputIPCManager) Start() error {
	if !atomic.CompareAndSwapInt32(&aim.running, 0, 1) {
		return nil
	}

	aim.logger.Debug().Str("component", AudioInputIPCComponent).Msg("starting component")

	// Initialize connection monitoring
	aim.monitoringEnabled = true
	aim.lastConnectionCheck = time.Now()
	atomic.StoreInt32(&aim.connectionFailures, 0)
	atomic.StoreInt32(&aim.recoveryInProgress, 0)

	err := aim.supervisor.Start()
	if err != nil {
		// Ensure proper cleanup on supervisor start failure
		atomic.StoreInt32(&aim.running, 0)
		aim.monitoringEnabled = false
		// Reset metrics on failed start
		aim.resetMetrics()
		aim.logger.Error().Err(err).Str("component", AudioInputIPCComponent).Msg("failed to start audio input supervisor")
		return err
	}

	config := InputIPCConfig{
		SampleRate: GetConfig().InputIPCSampleRate,
		Channels:   GetConfig().InputIPCChannels,
		FrameSize:  GetConfig().InputIPCFrameSize,
	}

	// Validate configuration before using it
	if err := ValidateInputIPCConfig(config.SampleRate, config.Channels, config.FrameSize); err != nil {
		aim.logger.Warn().Err(err).Msg("invalid input IPC config from constants, using defaults")
		// Use safe defaults if config validation fails
		config = InputIPCConfig{
			SampleRate: 48000,
			Channels:   2,
			FrameSize:  960,
		}
	}

	// Wait for subprocess readiness
	time.Sleep(GetConfig().LongSleepDuration)

	err = aim.supervisor.SendConfig(config)
	if err != nil {
		// Config send failure is not critical, log warning and continue
		aim.logger.Warn().Err(err).Str("component", AudioInputIPCComponent).Msg("failed to send initial config, will retry later")
	}

	aim.logger.Debug().Str("component", AudioInputIPCComponent).Msg("component started successfully")
	return nil
}

// Stop stops the IPC-based audio input system
func (aim *AudioInputIPCManager) Stop() {
	if !atomic.CompareAndSwapInt32(&aim.running, 1, 0) {
		return
	}

	aim.logger.Debug().Str("component", AudioInputIPCComponent).Msg("stopping component")

	// Disable connection monitoring
	aim.monitoringEnabled = false

	aim.supervisor.Stop()
	aim.logger.Debug().Str("component", AudioInputIPCComponent).Msg("component stopped")
}

// resetMetrics resets all metrics to zero
func (aim *AudioInputIPCManager) resetMetrics() {
	atomic.StoreInt64(&aim.metrics.FramesSent, 0)
	atomic.StoreInt64(&aim.metrics.FramesDropped, 0)
	atomic.StoreInt64(&aim.metrics.BytesProcessed, 0)
	atomic.StoreInt64(&aim.metrics.ConnectionDrops, 0)
}

// WriteOpusFrame sends an Opus frame to the audio input server via IPC
func (aim *AudioInputIPCManager) WriteOpusFrame(frame []byte) error {
	if atomic.LoadInt32(&aim.running) == 0 {
		return nil // Not running, silently ignore
	}

	if len(frame) == 0 {
		return nil // Empty frame, ignore
	}

	// Check connection health periodically
	if aim.monitoringEnabled {
		aim.checkConnectionHealth()
	}

	// Validate frame data
	if err := ValidateAudioFrame(frame); err != nil {
		atomic.AddInt64(&aim.metrics.FramesDropped, 1)
		aim.logger.Debug().Err(err).Msg("invalid frame data")
		return err
	}

	// Start latency measurement
	startTime := time.Now()

	// Update metrics
	atomic.AddInt64(&aim.metrics.FramesSent, 1)
	atomic.AddInt64(&aim.metrics.BytesProcessed, int64(len(frame)))
	aim.metrics.LastFrameTime = startTime

	// Send frame via IPC
	err := aim.supervisor.SendFrame(frame)
	if err != nil {
		// Count as dropped frame
		atomic.AddInt64(&aim.metrics.FramesDropped, 1)

		// Handle connection failure
		if aim.monitoringEnabled {
			aim.handleConnectionFailure(err)
		}

		aim.logger.Debug().Err(err).Msg("failed to send frame via IPC")
		return err
	}

	// Reset connection failure counter on successful send
	if aim.monitoringEnabled {
		atomic.StoreInt32(&aim.connectionFailures, 0)
	}

	// Calculate and update latency (end-to-end IPC transmission time)
	latency := time.Since(startTime)
	aim.updateLatencyMetrics(latency)

	return nil
}

// WriteOpusFrameZeroCopy sends an Opus frame via IPC using zero-copy optimization
func (aim *AudioInputIPCManager) WriteOpusFrameZeroCopy(frame *ZeroCopyAudioFrame) error {
	if atomic.LoadInt32(&aim.running) == 0 {
		return nil // Not running, silently ignore
	}

	if frame == nil || frame.Length() == 0 {
		return nil // Empty frame, ignore
	}

	// Validate zero-copy frame
	if err := ValidateZeroCopyFrame(frame); err != nil {
		atomic.AddInt64(&aim.metrics.FramesDropped, 1)
		aim.logger.Debug().Err(err).Msg("invalid zero-copy frame")
		return err
	}

	// Start latency measurement
	startTime := time.Now()

	// Update metrics
	atomic.AddInt64(&aim.metrics.FramesSent, 1)
	atomic.AddInt64(&aim.metrics.BytesProcessed, int64(frame.Length()))
	aim.metrics.LastFrameTime = startTime

	// Send frame via IPC using zero-copy data
	err := aim.supervisor.SendFrameZeroCopy(frame)
	if err != nil {
		// Count as dropped frame
		atomic.AddInt64(&aim.metrics.FramesDropped, 1)
		aim.logger.Debug().Err(err).Msg("failed to send zero-copy frame via IPC")
		return err
	}

	// Calculate and update latency (end-to-end IPC transmission time)
	latency := time.Since(startTime)
	aim.updateLatencyMetrics(latency)

	return nil
}

// IsRunning returns whether the IPC manager is running
func (aim *AudioInputIPCManager) IsRunning() bool {
	return atomic.LoadInt32(&aim.running) == 1
}

// IsReady returns whether the IPC manager is ready to receive frames
// This checks that the supervisor is connected to the audio input server
func (aim *AudioInputIPCManager) IsReady() bool {
	if !aim.IsRunning() {
		return false
	}
	return aim.supervisor.IsConnected()
}

// GetMetrics returns current metrics
func (aim *AudioInputIPCManager) GetMetrics() AudioInputMetrics {
	return AudioInputMetrics{
		FramesSent: atomic.LoadInt64(&aim.metrics.FramesSent),
		BaseAudioMetrics: BaseAudioMetrics{
			FramesProcessed: atomic.LoadInt64(&aim.metrics.FramesProcessed),
			FramesDropped:   atomic.LoadInt64(&aim.metrics.FramesDropped),
			BytesProcessed:  atomic.LoadInt64(&aim.metrics.BytesProcessed),
			ConnectionDrops: atomic.LoadInt64(&aim.metrics.ConnectionDrops),
			AverageLatency:  aim.metrics.AverageLatency,
			LastFrameTime:   aim.metrics.LastFrameTime,
		},
	}
}

// updateLatencyMetrics updates the latency metrics with exponential moving average
func (aim *AudioInputIPCManager) updateLatencyMetrics(latency time.Duration) {
	// Use exponential moving average for smooth latency calculation
	currentAvg := aim.metrics.AverageLatency
	if currentAvg == 0 {
		aim.metrics.AverageLatency = latency
	} else {
		// EMA with alpha = 0.1 for smooth averaging
		aim.metrics.AverageLatency = time.Duration(float64(currentAvg)*0.9 + float64(latency)*0.1)
	}
}

// checkConnectionHealth monitors the IPC connection health
func (aim *AudioInputIPCManager) checkConnectionHealth() {
	now := time.Now()

	// Check connection every 5 seconds
	if now.Sub(aim.lastConnectionCheck) < 5*time.Second {
		return
	}

	aim.lastConnectionCheck = now

	// Check if supervisor and client are connected
	if !aim.supervisor.IsConnected() {
		aim.logger.Warn().Str("component", AudioInputIPCComponent).Msg("IPC connection lost, attempting recovery")
		aim.handleConnectionFailure(fmt.Errorf("connection health check failed"))
	}
}

// handleConnectionFailure manages connection failure recovery
func (aim *AudioInputIPCManager) handleConnectionFailure(err error) {
	// Increment failure counter
	failures := atomic.AddInt32(&aim.connectionFailures, 1)

	// Prevent multiple concurrent recovery attempts
	if !atomic.CompareAndSwapInt32(&aim.recoveryInProgress, 0, 1) {
		return // Recovery already in progress
	}

	// Start recovery in a separate goroutine to avoid blocking audio processing
	go func() {
		defer atomic.StoreInt32(&aim.recoveryInProgress, 0)

		aim.logger.Info().
			Int32("failures", failures).
			Err(err).
			Str("component", AudioInputIPCComponent).
			Msg("attempting IPC connection recovery")

		// Stop and restart the supervisor to recover the connection
		aim.supervisor.Stop()

		// Brief delay before restart
		time.Sleep(100 * time.Millisecond)

		// Attempt to restart
		if restartErr := aim.supervisor.Start(); restartErr != nil {
			aim.logger.Error().
				Err(restartErr).
				Str("component", AudioInputIPCComponent).
				Msg("failed to recover IPC connection")
		} else {
			aim.logger.Info().
				Str("component", AudioInputIPCComponent).
				Msg("IPC connection recovered successfully")

			// Reset failure counter on successful recovery
			atomic.StoreInt32(&aim.connectionFailures, 0)
		}
	}()
}

// GetDetailedMetrics returns comprehensive performance metrics
func (aim *AudioInputIPCManager) GetDetailedMetrics() (AudioInputMetrics, map[string]interface{}) {
	metrics := aim.GetMetrics()

	// Get client frame statistics
	client := aim.supervisor.GetClient()
	totalFrames, droppedFrames := int64(0), int64(0)
	dropRate := 0.0
	if client != nil {
		totalFrames, droppedFrames = client.GetFrameStats()
		dropRate = client.GetDropRate()
	}

	// Get server statistics if available
	serverStats := make(map[string]interface{})
	if aim.supervisor.IsRunning() {
		serverStats["status"] = "running"
	} else {
		serverStats["status"] = "stopped"
	}

	detailedStats := map[string]interface{}{
		"client_total_frames":   totalFrames,
		"client_dropped_frames": droppedFrames,
		"client_drop_rate":      dropRate,
		"server_stats":          serverStats,
		"ipc_latency_ms":        float64(metrics.AverageLatency.Nanoseconds()) / 1e6,
		"frames_per_second":     aim.calculateFrameRate(),
	}

	return metrics, detailedStats
}

// calculateFrameRate calculates the current frame rate
func (aim *AudioInputIPCManager) calculateFrameRate() float64 {
	framesSent := atomic.LoadInt64(&aim.metrics.FramesSent)
	if framesSent == 0 {
		return 0.0
	}

	// Return typical Opus frame rate
	return 50.0
}

// GetSupervisor returns the supervisor for advanced operations
func (aim *AudioInputIPCManager) GetSupervisor() *AudioInputSupervisor {
	return aim.supervisor
}